Alarm signal system



Sept. 9, 194-1. c. POOL ETAL v 2,255,186

ALARM SIGNAL SYSTEM Filed May 18, 1958 3 Sheets-Sheet l uyo F'Q p er Sept. 9, 1941. c, 'POOL ET AL 2,255,186

ALARM SIGNAL SYSTEM Filed May 18, 1938 3 Sheets-Sheet 2 Sept. 9, 1941. c. POOL ETAL 2,255,186

ALARM SIGNAL SYSTEM' Filed May 18, .1958 3 Sheets-Sheet s Jial 25 W I I l Patented Sept. 9, 1941 wire r ALARM SIGNAL SYSTEM Clark Pool and Hugo F. Cypser, Brooklyn, N. Y.,

assignors to Signal Engineering & Manufacturing Company, New York, N. .Y.,

Massachusetts a corporation of 6 Claims.

The present invention relates to alarm signal 'systemaparticularly interior fire alarm systems,

commonly installed in schools, factories, hotels and other large buildings, andemploying a number of bells or other signals adapted to be sounded, or otherwise operated, in response to the actuation of any one of a number of alarm sending stations.

When installing an interior alarm signal system of the above indicated character, it is frequently necessary to provide a connection with .a street fire alarm box of .a city system, so that the city box will be tripped automatically, upon actuating any sending station of the interior fire alarm system. But such a city box connection should only be operative to signify the occurrence of a fire in the building protected by the interior alarm system, it being "highly undesirable to have a city box tripped, upon the occurrence of a fault in the interior system, or should it be desired to operate the interior system for the purpose of holding a fire drill.

According to the present invention, there is I provided an interior fire alarm system, including a connection with a city fire alarm box,

so arranged as to prevent the city box from being tripped, upon the occurrence of a fault in the system, or should it be desired .to operate the signals of the system for purposes of a fire 'drill. Therefore, the associated street fire alarm box will be tripped, and the city fire apparatus called, only when a station of the alarm system can be restored to a condition of complete supervision, following the sending of an alarm. The above and other advantageous features of the invention will hereinafter more fully appear from the following description, considered in connection with the accompanying drawings, in which:

:Fig. 1 is a schematic wiring diagram of, an

alarm signal system embodying the invention, with the "system in its normal condition of complete supervision.

Fig. 2 is a diagram similar to Fig. '1, illustrating operation of a city box trip coil, in response to actuation of a sending station of the interior alarm system.

Fig. 3 is'a diagram, illustrating operation of the interior alarm system, without affecting the trip coil of the city box.

Fig. 4 is a view inside elevation coil relay.

Fig. 5 illustrates a mounting for the trip coil relay.

Fig. 6 is a View in side elevation of the dispatching mechanism of a sending station of the interior alarm system. a

Fig. 7 is a view in end elevation of the parts shown in Fig. 6, as viewed from the left.

Fig. 8 is a View similar to Fig.6, illustrating the manner of operating the dispatching mechanism, Without energizing the trip coil of the city box. a

Fig. 9 is a front view of the station box, on a reduced scale. 7

Like reference characters refer to like parts in the different figures.

Referring first to Fig. :1, the system comprises a main contactor-relay A, providing an energizing winding 1 havingone terminal thereof connected at a junction 2 to one of a pair of supply mains 3 and 4, energized from a suitable source'of electrical energy. The other terminal of the relay winding I is connected to the movable arm 5 of a station control relay B having an energizing winding 6, also connected to the junction point 2 leading to the supply main 3. With the windof the trip .ing 6 energized, as shown, the arm 5 is maintained in engagement with a stationary contact I, and this contact I isconnected to the stationary contact 8 of a city box control relay 0. The relay C providesa'winding 9 having one terminal connected to the junction point 2, and with the winding 9 energized, one movable arm ii) of the relay C is maintained in engagement with the contact 8.

The arm ll) of the relay C is connected 'to'on'e terminal of the winding ll of a supervisory relay D, the other terminal of which is connected in series with the operating windings l2 and balwinding M connected to one of a pair of normally closed latch controlled contacts l5, the'purpose of which will be hereinafter referred to.

The other contact i5 is connected in series with balancing resistor [B for relay E and signal circuit protective resistor H, to the other supply main 4.

One terminal of the winding 6 of the station control relay B is connected to the junction point 2 leading to supply main 3, and the other terminal of this winding is connected in series with pairs of normally closed coding contacts [8 of a number of alarm sending stations S of the interior fire alarm system. Each pair of station contacts l8 cooperates with the code wheel [9 of a dispatching mechanism, hereinafter described, and as long as the station S remains in a non-operating condition, the coding contacts I3 remain closed. The contact l8 of the last station of the system is connected to the supply main 4, through a station protective resistor 20.

The winding 9 of the city box control relay C, with one terminal connected to the junction point 2, hasits other terminal connected in series with pairs of normally closed contacts 25, forming part of the dispatching mechanism of each station S. The contacts 21 are maintained in engagement by a cam device 22, forming part of the dispatching mechanism of a station S, and there will be hereinafter described an arrangement whereby the contacts can only be opened when a station S is actuated for the purpose of sending a fire alarm. The contacts 2| of the last station S are connected to the supply main 4 through a protective resistor 23.

As previously pointed out, the system of the present invention provides an arrangement whereby the fire alarm box of a city system may be tripped and a portion of such a street box is indicated at 24 as providing a trip coil 25, which, upon being energized, will release the dispatching mechanism of the box so as to transmit an alarm to the central station. The trip coil 25 is adapted to be energized from the supply mains 26 of the city system, but the coil 25 is normally shunted out of circuit by conductors 21 leading to the trip coil relay E. The conductors 21 are connected to a pair of normally closed contacts 28, and these contacts 28 are in turn connected in parallel with a stationary contact Z9 normally engaged by a movable arm 39 of the relay E. The purpose of the parallel connected contacts 28 and contact 29 with arm 30, will hereinafter more fully appear, and it is sufficient to state at this point, that the city box trip coil 25 cannot be energized until the winding [4 of the trip coil relay E has been fully energized, so as to separate contacts 28 and to move arm 30 out of engagement with stationary contact 29.

All of the current carrying elements entering into the system described thus far are under continuous electrical supervisiomand there are three supervisory circuits, which may be conveniently traced, starting from the main 4. The signal and main contactor supervisory circuit includes the resistors I! and 16, from which the current flows through the normally closed contacts I5, and the winding [4 of the trip coil relay, and then through the windings l2 and balancing resistors 12a of the several sections of signals. From the signals E3, the supervisory current traverses the winding ll of the supervisory relay D, the normally engaged arm I0 and contact 8 of the city box control relay 0, contact 1 and arm 5 of the station control relay B, and finally the winding l of the contactor A, which is connected to the junction point 2 leading to the grounded supply main 3. The value of this supervisory current is not sufiicient to energize either the winding l of the contactor A, signal windings I2, or the winding l4 of the trip coil relay E, although it is sufiicient to energize the winding H of the supervisory relay D, and so maintain one arm SI of this relay out of engagement with a stationary contact 32.

The arm 3| is connected to one terminal of the winding 33 of a trouble signal 34 of any desired type, with the other terminal of winding 33 connected to one side of a source 35 that is preferably independent of the source of electrical energy supplying the signal system mains 3 and 4.. The other side of source 35 is connected to the contact 32 of the supervisory relay D, so that while the winding ll remains energized, due to the flow of supervisory current therethrough, the trouble signal 34 remains silent. It is apparent, however, that a fault, such as a break or ground occurring in the supervisory circuit traced above, will result in energization of the trouble signal 34, to indicate the existence of the fault.

A second supervisory circuit for the sending stations S may be traced from the main 4, through the station resistor 20 and then through the normally closed pairs of contacts l8 of the sending stations S. The circuit extends from the stations through the winding 6 of the station control relay B to the junction point 2 leading to the grounded supply main 3. The value of this supervisory current is sufiicient to energize the winding 6 and cause its arm 5 to be maintained in engagement with the stationary contact I. Therefore, any fault in the circuits of the station contacts will result in the relay B dropping back, so as to break the main supervisory circuit at the contact I and cause deenergization of the supervisory relay winding II, with resulting operation of the trouble signal 34.

A third supervisory circuit extends from the supply main 4 through the resistor 23 to the pairs of normally closed contacts ill of the several stations, and then through the winding 9 of the city box control relay C to the junction point 2 leading to the grounded supply main 3. The value of this supervisory current is suflicient to energize the winding 9 and cause it to maintain the arm I0 in engagement with stationary contact 8 in the main supervisory circuit. Therefore, the occurrence of a fault in the circuits including the normally closed control contacts 2!, will result in dropping back of the relay C to interrupt the main supervisory circuit at the contact 8 and cause energization of the trouble signal 34.

When a station S is actuated, for the purpose of giving an alarm, operation of its dispatching mechanism, hereinafter described, causes rotation of the code wheel l9, and the coding projections I 9a on this wheel cause successive opening and closing of the associated station contacts l8 for a predetermined number of rounds. Upon the first opening of the contacts Hi, the winding 6 of the station control relay B is deenergized, and the relay arm 5 drops, to engage a stationary contact 36, as shown in Fig, 2. This contact 36 is connected by a conductor 37 to the main 4 beyond the stations S, so that the main contactor winding l becomes fully energized, upon the first opening of the station contacts I8. causes its movable contact arms 38 and 39 to engage spaced pairs of stationary contacts 40,

Full energization of the winding l' 4! and 42, 43, respectively, thereby establishing -operating circuits for the signals l3, as well as partially establishing an energizing circuit for the winding l4 of the trip coil .relay 'Upon bridging of the spaced stationary contacts 40 and 4| by the arm 38 of the contactor A, a circuit isestablished from the supply main 4, through conductors 44 and 45 to a junction point 46 between the windings l2 of the signals I3. From this point, the current divides and flows through the signal windings l2 and parallel conductors 41a and 47b to the then engaged contactor arm 39, contacts 42 and 43, and grounded supply main 3. This current flow is indicated by the arrows in Fig. 2, and it is obvious that successive opening and closing of the station contacts l8 will result in successive energizations of the signal windings l2, to cause a code to be sounded in accordance with the arrangement of the code projections [9a .on the code wheel l9.

.It is to :be noted that the energizing circuit for the contactor winding I is such thata-ground on a station circuit will not cause the signals l3 to sound, .although a break will causethe signals to sound one stroke, coincidentally with operation of the trouble signal 34. Since the energizing current for winding I must pass through resistor 20, as indicated by arrows in Fig. 2, any

ground on a station circuit will cause relay B to connect'this ground to non-grounded terminal of winding l.

As previously pointed out, the present invention contemplates the provision of an arrangement whereby the trip coil 25 of the city box 24 will be energized to operate the connected city box, in response to actuation of a station S to sound a fire alarm in the system. To this end, the dispatching mechanism of each station S, provides means whereby the cam device22 will be operated to cause separation of the control contacts 2 I, immediately upon setting the dispatching mechanism in operation. The contacts 2| are shown disengaged in Fig. 2,.from which it is evident that the circuit of Winding 9 of the city control box relay will be interrupted. Upon deenergization of the Winding 9, an arm 48 of the relay C will fall, to engage a contact 49, thereby establishing a circuit through conductor 50 from contact arm 38 of contactor A, which is then connected to supply main 4 through conductor 44. This circuit is continued from th arm 48 through conductor 5| to a stationary contact 52 of the supervisory relay D, which contact 52 is then engaged by an arm 53, due to the previous deenergization of the winding l l, upon breaking of the main supervisory circuit at the contact I of the station control relay B. Upon engagement of the contact '52 by th arm 53, a circuit is established through conductor 54 to a junction point 55 between the resistors I 6 and [1, thereby cutting the resistance I! out of circuit with the trip coil 4 relay winding l4.

Since the other terminal of the trip coil winding I4 is connected by the conductor 41a to the contact 42 of the main contactor A, which contact is then connected to supply main '3, deenergization of city box control relay C with the contactor A energized, causes full energization of the winding M, with resulting opening of the parallel pairs of contacts 28 and 29, 30. When this occurs, the shunt around the terminals of the trip coil 25 is removed, thereby causing energization of the 001125 and tripping of the normally wound dispatching mechanism of the city Fromtheitoregoing:description of'the mannerrin which .an 'energizin'g'circuit for the windingl-l of the trip ;coilirelay E is established, it is evident that the winding 14 :can be :energized only when deenergization'of the relayC is accompanied -'by energization of the contactor 2A and deenergiza- 'tion of the supervisory relay 13.. Therefore an accidental *break,"origround, in eitherthe city box control circuit, :or the trip coil "relay circuit, will not cause tripping of the city box 24, nor will failure of the source supplying the mains 3 and 4 haveza'nyrefiect'on the city box.

As best shown in Fig. 4, the city trip coil :relay E is .so constructed that the possibility :of the shunting contacts28 :and Z9, '30 becoming .accidentally disengaged, is eliminated. For this purpose, the contacts 28'aremounted :above the magnetic core 56 of the relay E, with the :contacts initially flexed, .so that they will remain tightly in engagement. 'The "stationary contact 29 .is mounted on a bracket 51, with the arm3fl carried :by a magnetic armature '58, pivoted on the core :56, :so that the "arm 31] rests'against 'contact 29, with the winding l4 deenergized. The armature also carries an upwardly .extendingrod '59 terminating below:an extension 280. of the upper contact 28. Upon'energization of the winding 14, upward movement of the armature 58 causes the arm 39 to first leave the cont'act'29,-but the rod 59 does not separate the contacts 28 untilzthe armature 58 has been fully attracted to the :dotted line position. Thusany jarring .of the relay E, which might tend to separate the arm 30 from the contact 29 upon slight movement ofthe armature, will not energize the city box trip coil 25, since the shunt around the trip coil-will be maintained by the contacts 28. Furthermore,-

breakage of a contact 28 will not affect the shunt maintained by the engaged contact 29 andarm .30.

In order to insure that the connected city fire alarm box'24 will 'be rewound after energization of the trip coil 25 by the relay E, provision is made for locking up this relay. The contacts l5, which are included in the main supervisory circuit in series with the winding 14, are'mounted above the contacts 28, with a connection 600i insulating material between the contact extensions 28a and 15a. Consequently, when upward movement of the armature 58 causes the rod 59 to engage the contact extension 2Ba,the contacts i5 will be separated at the same time as the contacts 28, thereby opening the circuit of'the winding I4.

In order to prevent the armature 58 from dropping back, a latch BI, pivoted at62, provides an arm 6la, normally resting against the end of the armature 58, when the latter occupies its lower position. When the armature 58 is raised to the dotted line position, in response to energization of the Winding l4, thela'tch arm Bla swings to the left to engage its end .under the extremity of the armature 58. Consequently, the armature 58 will bemechanically locked in its attracted position, with the contacts l5 open, even though the winding .14 is then deenergized.

With the armature 58 thus locked up, after operation of the :relay E to energize the city box trip coil 25, the trouble signal 34 will continue to operate, due to the break in the main supervisory circuit at the contacts I 5. It is obvious that this condition will continue to :eXist, even though the actuated station 5, which initially caused en- 'ergization of the relay E, has been restored'to normal condition by replacing the broken glass and closing the door, as will be hereinafter described. Therefore, the continued operation of the trouble signal 34 will call attention to the fact that the relay E is still latched up, and that the connected city box should be rewound. In order to'unlatch the relay E, it is only necessary to turn the latch lever 6|, so as to disengage the arm 6|a from the end of the armature 58. For

this purpose, a normally retracted plunger 63 is provided, which terminates beneath the end of a second latch lever arm 6| b that occupies a substantially horizontal position, as shown in dotted lines, when the armature 58 is latched up.

It is to be noted that the conductors 21 leading to the relay E are the only connection between the city box 24 and the interior alarm system, so that the city box connection is not really a part of the system. Furthermore, if desired, the relay E can be mounted adjacent to the box 24, as indicated diagrammatically in Fig. 5, with leads 64 extending outside to the relay under complete supervision. With such a mounting, unlatching of the relay E, in response to continued operation of the trouble signal 34, is accompanied by rewinding of the tripped box 24.

Should it be desired to actuate a station S to hold a fire drill, provision is'made for operation of the interior alarm system, without energizing the trip coil 25 of the box 24 of the city system.

'For' this purpose, each station box can be operated by a suitable key, in possession of a person in authority, with the operation of the key at a station S serving to render the cam device 22 ineffective to open the control contacts 2|. In Fig. 3, a key K is shown, diagrammatically, as having been operated so as to prevent turnin of the cam device 22, so that subsequent operation of the dispatching mechanism in the usual manner, has no effect on the contacts 2|, and the city box trip coil 25 remains shunted out during the operation of the signals l3 of the interior system, for the purpose of a fire drill. With the contacts 2| thus held closed, successive energizations of the main contactor A have no effect on the winding M of the trip coil relay, since the previously traced energizing circuit for the winding l4 remains open between the contact 49 and the arm 48 of the then energized city box control relay C. When the key K is withdrawn from thedispatching mechanism at the actuated station, provision is made for holding the contacts 2| closed until the station isrestored to its original condition, after the sending of a predetermined number of rounds of code signals has been completed. A dispatching mechanism capable of automatically functioning inthe above indicated manner, is disclosed in the co-pending application of John H. Wheelock and Ferdinand F. Humphreys, Serial No. 177,284 filed November 30, 1937,

and the essential elements of this mechanism will next be pointed out with reference to Figs. 6 to 9, inclusive.

Referring now to Figs. 6 and 7, one form of dispatching mechanism for use in a system embodying the invention, is mounted in a box 65 having a front 65a, on which a door 66 is hinged. The door 66 provides an opening 61 normally covered by a glass 68, which is broken in order to permit opening of the door, in response to operation of a latch mechanism, hereinafter described. When the door 68 has been opened, the mechanism is adapted to be actuated by a hand lever 69, accessible from the front of the box, as

shown in Fig. 9. The lever 69 is mounted on'a shaft 10, and turning of the lever in the direction of the arrow in Fig. 6, causes a toothed Sector II to turn a pinion 12, mounted on'a shaft 13. This shaft 13 is connected to a spring M, shown in dotted lines in Fig. 7, and turning of the lever 69 causes the spring to be wound. Consequently, upon release of the lever 69', the

tension of the wound spring M actuates the dis patching mechanism, to cause rotation of a shaft 15, driven from. the shaft l3 through suitable gearing l6.

The code wheel I 9 of a station S is mounted on the shaft 15, and the ratio of the gearing I8 is such that the code wheel l9 makes several complete revolutions, in response to actuation of the lever 69 to wind the spring 14, by turning the shaft 13 through a portion of one revolution. The projections |9a on the code wheel, are adapted to engage the operating portion Ha of a lever ll so as to open and close the contacts |8,'shown in dotted lines, in accordance with the codesequence, whereby to cause operation of the signals 3 in the manner previously described.

The cam device 22, previously described as normally maintaining a pair of contacts 2| in engagement, consists of a pair of similar cams 18 and 19, mounted one behind the other on the spring shaft 73. While the cams are normally free to turn on the shaft 13, there is sufficient friction between these cams to cause them to turn in unison, unless separately restrained, as will be later described. The inner contact 2| provides an operating finger 80, which is suflicie'ntly wide so as to extend over both cams I8 and 79, and consequently, the contacts 2| are maintained in closed position as long as either of the two cams 18 or 19 is in the position of Fig. 6.

The outer cam 18 provides an arm 8|, having an extension 8|a projecting into the plane of movement of a plate 82 carried by a plunger 83 adapted to be actuated through a mechanism hereinafter described, under the control of the key K, previously referred to. It is sufficient to state at this point that by means of the key K, the plate 82 can be moved to the position of Fig. 8, so as to prevent the cam 18 from turning with the cam 19, in which position the'cam l3 maintains the contacts 2| closed, irrespective of the position of the other cam 19.

The inner cam 19 provides an arm 84, which extends under the arm 8| and provides a projection 84a extending into the path of movement of the code projections |9a on the code Wheel l9, see Fig. '7. The inner cam 19 also provides an extension 85, which terminates adjacent a depression 88 in a detent spring 81. When the cam 18 is turned by engagement of a code projection I911 with its arm 84, the extension 85 is snapped into the depression 86 of the spring 81, to yieldingly maintain the cam 19 in a position in which it will permit opening of the contacts 2|.

The inner cam 19 also carries a pin 88 extending into the path of movement of a transverse pin 89 carried by the spring shaft 13. The relation between the pins 88 and 89 is such that as the shaft 13 returns to its normal position, after functioning of the dispatching mechanism, the pin 89 engages the pin 88 and restores the inner cam 18 to the position of Fig, 6, which meve ment disengages the cam extension 85 from the depression 86 of the detent spring 81. This restoring movement also returns the cam 18 to the position of Fig. 6, in alinement with the cam 19,

by reason of the tendency efthe-c'amslaand [9 to move in unison.

A third cam 90 is secured to the outer end of the shaft 13, and provides an annular flange 9|, having a notch 92 in the rim thereof. With the parts occupying the normal non-operating position of Fig. 6, the notch 92 is in alinement with an extension 93 of the plate 82'. The extension 93 is of such width as to pass through the notch 92 of the rim cam 99, when the plate 82 is shifted to the left, as shown in Fig. 8. In either position of the plate 82, however, the flange 9! can turn with the shaft 13, so that the plate 82 cannot be shifted during operation of the dispatching mechanism. The plate 82 and its associated plunger 83 is normally maintained in the position of Fig. 6 by a spring 94, in which position a notch 95 at one end of the plate is opposite to the bent-over and 96a of a latch finger 96. A second notch 9'! is also provided by the plate 82, and the latch finger 95 is also adapted to cooperate with this notch, as shown in Fig. 8.

A spring 98 normally urges the latch finger 96 in the direction of the plate 82, but with the door 66 closed, as shown in Fig. 6, a lug 99, projecting inwardly from the door, bears on a projection 95b of the latch 96, so as to maintain the end 9611 of the latch out of engagement with the plate notch 95. Upon opening of the door 66, withdrawal of the lug 9'9 permits the spring 98 to move the latch 95 into engagement with one or the other of the two plate notches 95 or 91, in accordance with the position of the plate when the door is opened.

The plate operating plunger 83 is surrounded at one end by a. sleeve cam use, turnable in a tubular housing ltl, in which the plunger 83 is longitudinally movable. The cam I99 provides a helical face I92, the base of which is engaged by a pin Hi3, carried by the plunger, so that turning of the cam. I99 will shift the plunger 83 and plate 82. to the position of Fig. 8, wherein a surface 82a. of the plate bears on the extension am of the arm 81 of the camlii.

The sleeve cam I99 also providesv a transverse e groove [04, which, with the door 66 closed, isengaged by a. tongue I95 provided at the end of a shaft I96, forming part of the door latch mechanism. The shaft 196 is turnable in an opening H11 extending through the door 65, and its outer end provides a second tongue 198, of such form as to be received in a notch 199 provided at the end of the key K, shown adjacent to door, in Fig. 6. The key also provides a pin 19, adapted to. pass through notches HI formed at the entrance to the opening I91, see Fig. 9. Passage of the pin Ill] through the notches HI, insures registration of the outer shaft tongue I98 with the key notch I99, when the key is inserted, in order to operate the sleeve cam I90 and the door latching mechanism, which will next be described.

In Fig. 9, the door 66 is shown on a reduced scale, and is provided with a latch mechanism of the type shown in Ebert Patent No. 1,990,727, dated February 12, 1935. The latch mechanism consists of an arm H2, shown in dotted lines behind the glass 68, with one end of the arm engaged behind a head 3a formed at the end of a stud H3 projecting from the front of the box, as shown in Fig. 8. The arm H2 is loosely pivoted at H4, and its opposite end bears on the conical head H5 of a plunger H6 that is pressed by a spring H1 against the glass 58. A spring H8- tends to hold the latch arm H2 in engagement with the plunger head H5, in which position the opposite end engages behind the stud head So, to hold the door 66 closed.

When it is desired-to operate thebox forthe purpose of sending an alarm,thegl'ass 6B is broken, whereupon the spring l l 'l forces the plunger H6 outwardly, into the space previously occupied by the glass. The cone-shaped plunger head H5 is thereupon withdrawn from engagement with the latch arm H2, thereby permitting the spring H 8 to turn the arm in a counter-clockwisedirection, and' disengage its opposite end from the stud- M 3. The door 66 may then be swungopen, to give access totlie handle 69', which is then pulled down and released. It' is to be noted that openingof the door 66 withdraws the'lug 99 from the latch finger 96 thereby permitting thespring 98 to move the end.

96a ofthe finger $16 into the notch 950i theplate 82. This insuresthat the plate 82- cannotbe moved during the operation of the mechanism for the purpose of sending an alarm throughout the system, and at the same timertripping the associated city box.

When the handle 69 is pulled down, the" resulting turning of the shaft 13 as the spring is wound, separates the shaft pin 89' from the cam pin 88 As soon as the Wound spring shaft 13 is released, the code wheel starts to turn, and the first code projection l9a turns the lever 11 to open the station coding contacts E8; The first code projection [9a. alsoturns the arm 84 of the inner cam 79, soas to move the cam extension 85 into the depression 8'9 ofthe detent spring 8?, so that both cams l8 and 79 are, in eifect', locked in thedotted line position of Fig. 6, with the contacts 21 open, duringtheremainder of the operation of the dispatching mechanism. The. resulting energization'of' contactor A, accompanied by deenergization of relays C and D, causes the city box tobe tripped almost simultaneouslywith operation of the'signals 1-3. As the dispatching mechanism runs down, following the sending of a number ofcode impulses by the signals t3, the pin 89 on shaft 13 engages the pin- 88 on the cam 19, and thereby restores both cams-to the position-of Fig. 6, wherein the contacts 2+ are maintained inengagement by the finger 80.

Should it be desired to operate a station S for the purpose of a fire drill, the key K is inserted in the opening Ill-I, with-its notch H39 engaging the tongue E8 of the-latch shaft I96. The key K is then turned through an angle of approximately which has the effect of first locking the plate 82 in the position of Fig. 8; and then turning the latch arm H2 so as to permit the door 69 to be opened. The first result is obtained when thehelical face l92'of the sleeve cam I99; engages the plunger pin 53, thereby shifting the plunger 83' and its plate 82 to the left", into the position of Fig. 8. In-thisposition of the plate 82, it is impossible for the-cam 18' to be turned; due to the engagement of the extension 810' on its arm 8-1 with the plate face 82a. Further turning of the shaft I96 causes a cam projection H9 thereon to engage the: latch arm H 2 and shift the whole arm about the plunger 1 It as a pivot, so as to disengage the opposite end of'the arm from the latch stud 113-. The door may now be the city box trip coil- 25, due to the fact that" the cam 18 holds the contacts 2| closed, even though cam 79 has been moved away from finger 80.

The key K may then be withdrawn, after first turning it back so as to restore the sleeve cam I09 to its initial position. This, however, has no effect on the plunger 83, since the plate 82 is then locked by the latch finger 96, in the position of Fig. 8. In this position of the plate 82, it is also to be noted that the extension 93 is then positioned inside the flange 9| of the cam 90, due to its passage through the notch 92. Therefore, as soon as the shaft 13 is turned by operation of the handle 69, the plate 82 is locked against further movement, throughout the operation of the mechanism.

The above described cooperation between the plate extension 93 and the cam 9!], permits the door 66 to be closed and latched, after withdrawal of the key, so that the person who operated the box can go to another location, in order to watch the fire drill. With the plate 82 locked by the rim cam 95, the withdrawal of latch finger 86 by the lug 99, when the door is closed, has no efiect on the plate 82. That is to say, the spring 94 is ineiiective to return the plate 82 to its initial position, until after the mechanism has run down, and the extension 93 is again in alinement with the notch 92 of the flange 9|.

We claim:

1. In an electric signalling system, the combination with transmitting stations including normally closed contacts movable upon actuation of a station, signals, a trip coil for a sending station forming part of an independent system, a relay for energizing said trip coil, a main controller having a Winding in a closed supervisory circuit, including said signals and trip coil energizing relay, energizing circuits for said signals, including normally open contacts operable by said controller, with the flow of supervisory current through said controller winding being insufiicient to cause closure of its contacts, or to operate said signals or said trip coil energizing relay, of additional normally closed contacts at each transmitting station, and means responsive to the opening of both sets of contacts upon normal actuation of a station to increase the energization of said controller winding and cause closure of said signal operating circuits, and to cause completion of a separate circuit to operate said trip coil energizing relay.

2. In an electric signalling system, the combination with transmitting stations including normally closed contacts movable upon actuation of a station, signals, a trip coil for a sending station forming part of an independent system, a relay for energizing said trip coil, a main controller having a winding in a closed supervisory circuit including said signals and trip coil energizing relay, energizing circuits for said signals, including normally open contacts operable by said controller, with the flow of supervisory current through said controller winding being insufificient to cause closure of its contacts or to operate said signals, or said trip coil energizing relay, of means responsive to the opening of the contacts at any station to increase the energization of said controller Winding and cause closure of said signal operating circuits, additional normally closed contacts at each station normally opened with said first-named contacts to cause operation of said trip coil energizing relay, and means at each station to prevent opening of said second-named contacts with said first-named contacts.

3. In an electric signalling system, the combination with transmitting stations, each providing independent sets of normally closed contacts, signals, a trip coil for the sending, station of a separate system, a relay for energizing said trip coil, and a circuit controller for operating said signals, of means responsive to the actuation of a station to open one set of contacts to cause energization of said controller and operation of said signals, other means normally responsive to actuation of a station to open the other set of station contacts and cause operation of said trip coil energizing relay, and means for selectively preventing the opening of said lastnamed contacts upon actuation of a station.

4. In an electric signalling system, the combination with transmitting stations, each providing independent sets of normally closed contacts, signals, a trip coil for the sending station of a separate system, a relay for energizing said trip coil, and a circuit controller for operating said signals, of means responsive to the actuation of a station to open one set of contacts to cause energization of said controller and operation of said signals, other means normally responsive to actuation of a station to open the other set of station contacts and cause operation of said trip coil energizing relay and key-operated means to permit actuation of a station without opening of said last-named contacts.

5. In an electric signalling system, the combination with transmitting stations each providing independent sets of normally closed contacts, signals, a trip coil for the sending station of a separate system, a relay for energizing said trip coil, and a main controller having a winding in a closed supervisory circuit including said signals and trip coil energizing relay, With the flow of supervisory current insufiicient to cause operation of said signals, or of said trip coil energizing relay, of means responsive to the actuation of a station to open one set of contacts to increase the energization of said controller winding and cause operation of said signals, other means normally responsive to actuation of a station to open the other set of station contacts and cause operation of said trip coil energizing relay, and means for selectively preventing the opening of said last-named contacts upon actuation of a station.

6. In an electric signalling system, the combination with transmitting stations each providing independent sets of normally closed contacts, signals, a trip coil for the sending station of a separate system, a relay for energizing said trip coil, and a main controller having a winding in a closed supervisory circuit including said signals and trip coil energizing relay, with the flow of supervisory current insufficient to cause operation of said signals, or of said trip coil energizing relay, of means responsive to the actuation of a station to open one set of contacts to increase the energization of said controller Winding and cause operation of said signals, other means normally responsive to actuation of a station to open the other set of station contacts and cause operation of said trip coil energizing relay, and key-operated means for locking said last-named contacts against opening upon actuation of a station.

CLARK POOL.

HUGO F. CYPSER, 

